The applicants' long term objective is to validate a non-invasive, non-radioactive breath test for monitoring gastric motility. The test will be used to identify patients with gastroparesis (impaired gastric emptying) and monitor the effectiveness of their treatment. Gastroparesis has been identified in a large percentage of patients with insulin dependent and non-insulin dependent diabetes mellitus, gastroesophageal reflux disease, and non-ulcer dyspepsia. These ailments affect more than 32 million Americans. The current diagnostic method, scintigraphy, is used infrequently because it is expensive and the availability is limited. A practical, reliable, and inexpensive test to measure gastroparesis is important to promote treatment decisions based on confirmed diagnosis. The experiments in Phase I will validate the breath test against the current diagnostic method and demonstrate its ability to monitor treatment. The test will be unique as the first commercially available and FDA approved breath test for gastric motility. It has enormous commercial application because the test has both research and clinical use. It will assist pharmaceutical companies to determine the efficacy of promising drugs and will help physicians identify and monitor treatment in patients afflicted with gastroparesis.